Not sure, I never tried. Why would you want to?I have another question for the MP-40 owners here: is it possible to save and easily switch between different speaker configurations? (I.e. 5.2 for movies, 2.2 for music)
I have two MP-40s. I use one in a dedicated 2.2 room so that MP-40 is configured for 2.2 and the other is in my HT with a 5.3.2 configuration (Really it is a 5.1.2 with three independent subwoofer channels). When I playback 2 channel or 3 channel stereo on my surround system the MP-40 only plays the appropriate channels and the others are silent. I don't see what telling it to limit itself to a channel count would achieve beyond this.